<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <button id="box">Test</button>

    <script src="./index.js"></script>
    <script>
      let box = document.getElementById("box");

      let fn = throttle((num) => {
        console.log(num);
      }, 3000);

      box.addEventListener("click", fn.bind(this, 123), false);
    </script>
  </body>
</html>
